Proper nutrition is one of the most important environmental factors that affect the development of the young organism as well as the maintenance of good health in adulthood. The harmonious development of the young organism can be disrupted by both excess and deficiency of nutrients and by misbalance between them. The aim of this study was to assess the impact of diet on the waist circumference being an indicator of abdominal obesity in 17-18-year-old youth from Wroclaw and vicinity. The survey was conducted in selected secondary schools in Wroclaw that participated in the «Health-Promoting School» program in the period from November 2010 to May 2011. Quantitative nutritional survey was performed using the direct 24- hr dietary recall method repeated seven times. Calculations of the content of each nutrient and energy supply in the daily diet of surveyed students were made using the «Energy» V.4.1. software with a database created based on «Table of Composition and Nutritional Value of Food Products» by Kunachowicz et al. Abdominal obesity was found among 25.6% of girls and 15.6% of boys aged 17-18 years. Above-normal waist circumference was observed more frequently among the 18-year-old youth, and the differences were statistically significant. There was a statistically significant difference in energy and macronutrient intake that was dependent on both gender and particular percentile group. The supply of energy, compared with the relevant dietary guidelines (EAR), was too low for girls and boys, regardless of waist circumference, which was also, affected by the poor implementation of dietary allowances (RDA) for nutrients, especially for total carbohydrates, fiber and plant protein in daily meals. Meals of girls and boys with the smallest waist circumference provided energy and nutrients in amounts close to the relevant allowances (RDA), as opposed to diet of the surveyed with the waist above the 95th percentile. The coverage of norms for energy (EAR) and macronutrients (RDA) was closest to normal in the adolescents with the smallest waist circumference.